Macroscopically expanded, three-dimensional, apertured polymeric webs are generally known in the art.
As utilized herein, the term "macroscopically expanded", when used to describe three-dimensional plastic webs, ribbons and films, refers to webs, ribbons and films which have been caused to conform to the surface of a three-dimensional forming structure so that both surfaces thereof exhibit the three-dimensional pattern of said forming structure, said pattern being readily visible to the naked eye when the perpendicular distance between the viewer's eye and the plane of the web is about 12 inches. By way of contrast, the term "planar", when utilized herein to describe plastic webs, ribbons and films, refers to the overall condition of the web, ribbon or film when viewed by the naked eye on a macroscopic scale. In this context "planar" webs, ribbons and films may include webs, ribbons and films having fine-scale surface aberrations on one or both sides, said surface aberrations not being readily visible to the naked eye when the perpendicular distance between the viewer's eye and the plane of the web is about 12 inches or greater.
One macroscopically expanded, three-dimensional, apertured plastic web which is particularly well suited to transferring fluid deposited on one surface thereof to its opposite surface and thereafter isolating the transferred fluid from the wearer's skin is disclosed in commonly assigned U.S. Pat. No. 3,929,135 issued to Thompson on Dec. 30, 1975, and hereby incorporated herein by reference. Thompson describes a macroscopically expanded, three dimensional topsheet comprised of liquid impermeable material, but provided with a pattern of tapered capillaries, said capillaries having a base opening in the plane of the topsheet and an apex opening remote from the plane of the topsheet, said apex opening being in intimate contact with the absorbent pad utilized in the disposable absorbent bandage. The Thompson topsheet allows the free transfer of fluids from the wearer's body into the absorbent element of the device while inhibiting the reverse flow of these fluids. This provides a relatively much drier surface in contact with the user than had previously been obtainable.
Another macroscopically expanded, three-dimensional, apertured plastic web well suited for use as a topsheet on absorbent bandages such as sanitary napkins is disclosed in commonly assigned U.S. Pat. No. 4,342,314 issued to Radel and Thompson on Aug. 3, 1982, said patent being hereby incorporated herein by reference. The macroscopically expanded, three-dimensional plastic web disclosed in the Radel and Thompson patent exhibits a fiber-like appearance and tactile impression which has been favorably received by consumers when used as a wearer contacting surface.
According to the teachings of the aforementioned commonly assigned patents to Thompson and to Radel et al., plastic webs of the aforementioned type can be made by applying a fluid pressure differential to the web while it is supported on a three-dimensional forming structure until the web is macroscopically expanded to comply with the three-dimensional cross-section of the forming structure on which it is supported. When aperturing of the macroscopically expanded, three-dimensional web is desired, said fluid pressure differential is applied continuously until such time as aperturing of the web in areas coinciding with the apertures in the forming structure has been completed.
While single-phase forming processes of this general type have been successfully utilized in producing macroscopically expanded, three-dimensional, apertured plastic webs exhibiting many characteristics generally viewed as favorable by consumers, the majority of such single-phase processing techniques have been unable to deliver all of the desired characteristics in a single finished web structure, particularly at high production speeds.